Biomass boiler in-situ flue gas sampling system and operation method

Abstract

The invention relates to the technical field of boiler flue gas sampling, in particular to a biomass boiler in-situ flue gas sampling system and an operation method.The biomass boiler in-situ flue gas sampling system comprises a constant-speed sampling nozzle and a smoke dust sampling pipe, the constant-speed sampling nozzle is communicated with the smoke dust sampling pipe, the biomass boiler in-situ flue gas sampling system further comprises a flue gas heat preservation unit and a fly ash collecting device, and a ventilation support is installed at the bottom of the smoke dust sampling pipe; an air pipe connector is arranged at the bottom of the ventilation support. Under the high-temperature combustion environment of the biomass boiler, firstly, the flue gas temperature is kept unchanged during sampling through the flue gas heat preservation unit, then constant-speed sampling of flue gas is achieved through the flue gas acceleration nozzle arranged at the front end of the sampling system, particulate matter sampling is conducted on the flue gas through the flue gas sampling pipe on the premise that the temperature is not changed, and the sampling efficiency is improved. The gas-solid separation of the flue gas and the in-situ collection of the fly ash particles are realized, and the interference of condensation and deposition of gaseous inorganic substances and the like on residual ash particle sampling caused by the reduction of the temperature of the flue gas is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of boiler flue gas sampling, and in particular to an in-situ flue gas sampling system and an operating method for a biomass boiler. Background Art

[0002] Biomass energy has many advantages over other new energy sources: renewability, wide distribution, zero carbon emissions, etc. In the process of burning biomass in biomass boilers, an unavoidable problem will arise: the alkali metals in the biomass will turn into gaseous products, which will condense and form slag at low temperatures. In this case, the analysis of the combustion efficiency and ash formation mechanism of the biomass boiler will face a huge challenge, and it is impossible to obtain the precise particle occurrence form and flue gas composition in the furnace.

[0003] Obtaining the most realistic flue gas data and particulate matter emission data is crucial to the study of ash formation mechanism, which is also of great significance to preventing biomass boilers from being contaminated and coked, optimizing operation, and optimizing boiler design. At present, the commonly used sampling devices are basically water-cooled sampling guns, or introducing nitrogen dilution at the sampling inlet, but this method cannot prevent the condensation of gaseous inorganic matter and the combination with particulate matter during the conversion of high-temperature flue gas to low temperature, making it difficult to separate flue gas and particulate matter. Another sampling method is to directly connect a sampling tube to the flue gas outlet to separate the flue gas and smoke particles to achieve the purpose of sampling, but in this way, the sampling tube is easily blocked by particulate matter, affecting the normal sampling. Therefore, there is an urgent need for a new sampling device for biomass boilers. Summary of the invention

[0004] In view of the above-mentioned defects and problems, the present invention provides an in-situ flue gas sampling system and operation method for a biomass boiler, which can realize gas-solid separation of flue gas and in-situ collection of fly ash particles, prevent the condensation and deposition of gaseous inorganic substances caused by the decrease in flue gas temperature from interfering with the sampling of residual ash particles, and through a series of control coordination during the sampling process, can avoid the sampling tube being blocked by large particles of ash, thereby ensuring the sampling effect.

[0005] The solution adopted by the present invention to solve the technical problem is: an in-situ flue gas sampling system and an operating method for a biomass boiler, comprising an isokinetic sampling nozzle and a smoke sampling tube, the isokinetic sampling nozzle is connected to the smoke sampling tube, and also comprises a smoke insulation unit and a fly ash collection device, a ventilation support is installed at the bottom of the smoke sampling tube, a trachea joint is arranged at the bottom of the ventilation support, and a gas outlet is opened in the trachea joint on the ventilation support, the trachea joint is connected to an external vacuum pump through a sampling main air pipe, and a gas flow control device is installed on the sampling main air pipe The bottom end of the smoke sampling tube is penetrated by a vent support and is provided with a fly ash sampling tube, and the bottom of the fly ash sampling tube is inserted in a fly ash collecting device, and a flue gas acceleration nozzle is arranged inside the lower end of the smoke sampling tube, and the upper end of the fly ash sampling tube is located at the lower air outlet of the flue gas acceleration nozzle, and the flue gas acceleration nozzle is used to accelerate the flow velocity of the sampled flue gas; the flue gas insulation unit comprises a sampling insulation tube and an insulation oil barrel, and the sampling insulation tube is sleeved on the outer side of the smoke sampling tube, and the insulation oil in the insulation oil barrel can enter the sampling insulation tube to provide insulation for the smoke sampling tube; The fly ash sampling tube is provided with a sampling tube anti-blocking mechanism, including an anti-blocking box and a delayed start component which are mutually fitted. The upper end of the fly ash sampling tube movably penetrates the top of the anti-blocking box, and the lower end is fixedly penetrated through the bottom of the anti-blocking box. A piston block is matched and fitted in the anti-blocking box. The fly ash sampling tube is fixedly penetrated and fitted in the center of the piston block. A negative pressure chamber 1 is formed between the piston block and the anti-blocking box, and the negative pressure chamber 1 is connected with the sampling main air pipe through the air pipe 2. A compression spring is fitted on the fly ash sampling tube below the piston block in the negative pressure chamber 1, and the piston block is connected to the negative pressure chamber 1 through the compression spring. When the upper part of the fly ash sampling tube is blocked by particulate matter, the piston block can drive the top of the fly ash sampling tube to move downward due to the negative pressure, so that the blockage falls. A piston ring is matched inside the delayed start component, and a negative pressure chamber 2 is formed between the piston ring and the delayed start component. The negative pressure chamber 2 is connected with the sampling main air pipe through the air pipe 1. A limit assembly for positioning the piston block is arranged above the piston ring. The upward and downward movement of the piston ring can limit or release the limit of the piston block by the limit assembly. When negative pressure occurs in the system due to blockage, the delayed start component is first started by the negative pressure, and the limit on the piston block is first released by the limit assembly. Then the piston block is started again to drive the fly ash sampling tube downward. The delayed start component can provide an extension time for the cooperation between the anti-blocking box and the fly ash sampling tube.

[0006] Furthermore, a V-shaped rod is provided above the piston ring in the delayed start assembly, the outer end of the V-shaped rod is hinged to the inner wall of the sleeve, and the inner end is hinged to a horizontally arranged clamping rod, the inner end of the clamping rod is a downward inclined slope structure, the V-shaped rod is connected to the sleeve by a pull rope, and the piston ring is connected to the V-shaped rod by a pull rope, a guide sleeve is fixed to the side wall of the anti-blocking box, and the clamping rod is movably sleeved in the guide sleeve, and in a stable pressure state, the position of the clamping rod corresponds to the position of the piston block, and a positioning groove is provided on the piston block, and the clamping rod can limit the piston block through the positioning groove.

[0007] Furthermore, the sampling insulation tube is composed of an outer tube and a middle tube which are fitted into each other, and an insulation oil channel is retained between the outer tube and the middle tube. An insulation oil inlet is welded on the side of the outer tube, and an insulation oil outlet is welded on the side of the middle tube. The insulation oil barrel is connected to the insulation oil inlet and the insulation oil outlet through oil pipes respectively. The insulation oil in the insulation oil barrel enters the insulation oil channel through the insulation oil inlet, and then flows out through the insulation oil outlet, forming an insulation oil circulation.

[0008] Furthermore, a smoke temperature sensor is installed on the top of the smoke insulation unit, and an oil temperature sensor is installed on the insulation oil barrel. The smoke temperature sensor and the oil temperature sensor are used to measure the temperature of the smoke and the insulation oil to ensure that the insulation temperature of the smoke insulation unit is the same as the smoke temperature.

[0009] Furthermore, a connecting pipe is connected between the fly ash collection device and the smoke sampling tube, and the connecting pipe connects the upper part of the smoke acceleration nozzle in the smoke sampling tube with the fly ash collection device from the side to form a loop for balancing the pressure of the smoke sampling tube and the fly ash sampling tube.

[0010] Furthermore, a limit assembly for limiting the movement range of the piston block and the piston ring is provided in the anti-blocking box and the delayed start assembly, and the movement distance and position of the piston block and the piston ring can be limited by the limit assembly.

[0011] Furthermore, the connecting pipe is disconnected at a position close to the fly ash collecting device, and a filter box is installed at the disconnected position. A second filter screen is arranged in the filter box, and the second filter screen can prevent smoke particles from flowing back through the connecting pipe.

[0012] Furthermore, a filter screen is provided in the gas outlet, and the ventilation support can be removed from the bottom of the smoke sampling tube.

[0013] An operation method of an in-situ flue gas sampling system for a biomass boiler is completed by the following operations: a vacuum pump provides power for extracting smoke, smoke enters a smoke sampling tube through a constant speed sampling nozzle, a smoke temperature sensor receives a smoke temperature signal and transmits it to a control processor, the control processor adjusts the oil temperature and the oil temperature sensor according to the oil temperature sensor, and controls the insulation oil in the insulation oil barrel to enter the sampling insulation tube for circulation to provide insulation effect, ensuring that the temperature of the high-temperature smoke in the smoke sampling tube remains unchanged; smoke passes through a smoke acceleration nozzle arranged in the smoke sampling tube to achieve the purpose of accelerating the flow rate of smoke, in this process, due to inertia, particulate matter enters a fly ash collection device through the fly ash sampling tube, and smoke flows along the inner wall of the smoke sampling tube and is discharged through a gas outlet; a connecting pipe connects the fly ash collection device and the smoke sampling tube to balance the air pressure of the two, achieving the purpose of smooth falling of particulate matter. Through the above process, in-situ smoke sampling of a biomass boiler is achieved.

[0014] Beneficial effects of the present invention: The present invention aims at the high-temperature combustion environment of biomass boilers. First, the flue gas temperature is kept unchanged during sampling by a flue gas insulation unit. Then, a flue gas acceleration nozzle arranged at the front end of the sampling system is used to sample the flue gas at a constant speed. The flue gas passes through a smoke sampling tube to sample particulate matter without changing the temperature. This realizes gas-solid separation of the flue gas and in-situ collection of fly ash particles, thereby preventing interference with the sampling of residual ash particles caused by condensation and deposition of gaseous inorganic substances due to the decrease in flue gas temperature. By setting up a sampling tube anti-blocking mechanism, when blockage occurs above the fly ash sampling tube, the fly ash sampling tube can be pulled down a certain distance through the cooperation between the anti-blocking box and the pressure change, so that the blocked particles can fall from the top of the fly ash sampling tube. At the same time, before starting the anti-blocking box, the cooperation of the delayed start component can provide a period of delay for the control between the anti-blocking box and the fly ash sampling tube. Through the cooperation between the delayed start component and the anti-blocking box, the blockage of the fly ash sampling tube can be eliminated without causing too much impact on the normal sampling work of the fly ash sampling tube, thereby improving the efficiency and effect of in-situ sampling of flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the overall system diagram of the present invention; Figure 2 It is a schematic diagram of the structure of the smoke insulation unit of the present invention; Figure 3 It is a partial enlarged structural schematic diagram of the present invention; Figure 4 It is a schematic diagram of the structure of the sampling tube anti-blocking mechanism of the present invention; Figure 5 This is a schematic diagram of the cooperation between the sampling tube anti-blocking mechanism and the fly ash sampling tube of the present invention; Figure 6This is the second schematic diagram of the cooperation between the sampling tube anti-blocking mechanism and the fly ash sampling tube of the present invention; Figure 7 for Figure 3 The enlarged structural diagram at A in the middle; Figure 8 for Figure 4 Schematic diagram of the enlarged structure at point B.

[0016] In the figure: 1. Constant speed sampling nozzle; 2. Smoke sampling tube; 3. Smoke insulation unit; 31. Sampling insulation tube; 311. Outer tube; 312. Middle tube; 313. Insulation oil channel; 314. Insulation oil inlet; 315. Insulation oil outlet; 32. Control processor; 33. Insulation oil barrel; 34. Oil temperature sensor; 35. Smoke temperature sensor; 4. Ventilation support; 41. Gas outlet; 42. Filter one; 43. Air pipe joint; 5. Fly ash sampling tube; 6. Fly ash collection device; 7. Smoke acceleration nozzle; 8. Sampling tube anti-blocking mechanism; 81. Anti-blocking box; 811. Piston block; 812. Compression spring; 813. Positioning groove; 82. Delayed start assembly; 821. Sleeve; 822. Piston ring; 823. V-shaped rod; 824. Clamping rod; 825. Guide sleeve; 826. Tension spring; 827. Pull rope; 828. Breathing hole; 83. Auxiliary air pipe; 831. Air pipe one; 832. Air pipe two; 9. Connecting pipe; 10. Sampling main air pipe; 11. Vacuum pump; 12. Gas flow control valve; 13. Connection box; 14. Sealing gasket; 15. Filter box; 16. Filter screen two. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0018] See also Figure 1-8 , the present invention provides a technical solution of an in-situ flue gas sampling system and an operation method for a biomass boiler: Example

[0019] according to Figure 1As shown, it includes an isokinetic sampling nozzle 1, a smoke sampling tube 2 and a smoke insulation unit 3. The isokinetic sampling nozzle 1 is connected to the exhaust port of the boiler, and the smoke sampling tube 2 is installed in the smoke insulation unit 3. The isokinetic sampling nozzle 1 is connected to the smoke sampling tube 2 and is not connected to the smoke insulation unit 3. The smoke of the boiler enters the smoke sampling tube 2 through the isokinetic sampling nozzle 1, and the smoke can be insulated by the smoke insulation unit 3 when flowing downward in the smoke sampling tube 2. The bottom of the smoke sampling tube 2 is open and is equipped with a ventilation support 4. A gas outlet 41 is provided on the ventilation support 4, and a trachea joint 43 is installed at the bottom of the ventilation support 4. The gas outlet 41 is located in the trachea joint 43. The smoke sampling tube 2 is connected to an external vacuum pump 11 through the trachea joint 43 and the sampling main air pipe 10, and a gas flow control valve 12 is installed on the sampling main air pipe 10. The vacuum pump 11 is used to provide power for extracting smoke, and the gas flow control valve 12 is used to control the amount of smoke extracted. A fly ash sampling tube 5 is installed through the ventilation support 4 at the bottom air outlet of the smoke sampling tube 2, and the lower part of the fly ash sampling tube 5 is inserted in the fly ash collection device 6. A smoke accelerating nozzle 7 is arranged inside the lower end of the smoke sampling tube 2. The upper end of the fly ash sampling tube 5 is located at the lower air outlet of the smoke accelerating nozzle 7. The smoke accelerating nozzle 7 is used to accelerate the flow rate of the sampled smoke.

[0020] The vacuum pump 11 starts to evacuate the air, so that the flue gas flows downward in the smoke sampling tube 2. When the flue gas flows in the smoke sampling tube 2, the airflow is accelerated by using the smoke accelerating nozzle 7, so that the particles with large inertia cannot move around with the airflow and fall directly into the fly ash sampling tube 5. Then the particles pass through the fly ash sampling tube 5 and enter the fly ash collecting device 6 for collection. At the same time, the gas is discharged from the gas outlet 41 at the bottom of the smoke sampling tube 2, so as to achieve the physical separation of gas and particulate matter. A connecting pipe 9 is connected between the fly ash collecting device 6 and the smoke sampling tube 2. The connecting pipe 9 connects the upper part of the smoke accelerating nozzle 7 in the smoke sampling tube 2 with the fly ash collecting device 6 from the side, forming a loop for balancing the pressure of the smoke sampling tube 2 and the fly ash sampling tube 5, so as to achieve the purpose of making the pressure in the smoke sampling tube 2 and the fly ash collecting device 6 consistent, so that the particulate matter can smoothly enter the fly ash collecting device 6.

[0021] according to Figure 2As shown, the flue gas insulation unit 3 includes a sampling insulation pipe 31 and an insulation oil barrel 33. The sampling insulation pipe 31 is composed of an outer pipe 311 and a middle pipe 312 which are mutually nested, and an insulation oil channel 313 is formed between the outer pipe 311 and the middle pipe 312. An insulation oil inlet 314 is vertically welded on the side of the outer pipe 311, and an insulation oil outlet 315 is vertically welded on the side of the middle pipe 312. The air inlet ends of the insulation oil inlet 314 and the insulation oil outlet 315 are both exposed to the outside. The warm oil barrel 33 is connected to the insulation oil inlet 314 and the insulation oil outlet 315 through an oil pipe. An oil temperature sensor 34 is installed on the oil inlet pipe. The insulation oil in the insulation oil barrel 33 enters the insulation oil channel 313 through the insulation oil inlet 314, and then flows out through the insulation oil outlet 315, forming an insulation oil circulation, providing insulation effect for the flue gas flowing in the smoke sampling tube 2, preventing the gaseous inorganic matter in the flue gas from cooling and condensing, combining with particulate matter, and affecting the sampling results. A flue gas temperature sensor 35 is installed on the top of the flue gas insulation unit 3, and an oil temperature sensor 34 is installed on the insulation oil barrel 33. The flue gas temperature sensor 35 is used to measure the temperature of the flue gas, and the oil temperature sensor 34 is used to ensure that the insulation temperature of the flue gas insulation unit 3 is the same as the flue gas temperature.

[0022] The flue gas insulation unit 3 also includes a control processor 32, which is connected to the control of each component in the system. The control processor 32 can receive temperature measurement signals from the oil temperature sensor 34 and the flue gas temperature sensor 35, and control the oil in the insulation oil barrel 33 to flow into the insulation oil channel 313.

[0023] like Figure 7 As shown, a connecting box 13 and a sealing gasket 14 are provided above the fly ash collecting device 6, and the sealing gasket 14 is located in the connecting box 13. The fly ash sampling tube 5 is inserted into the fly ash collecting device 6 through the connecting box 13 and the sealing gasket 14, so as to ensure that the fly ash sampling tube 5 and the fly ash collecting device 6 form a closed space, and the connection between the connecting box 13 and the fly ash collecting device 6 is detachable, so that the fly ash collecting device 6 can be removed to take away the collected smoke particles.

[0024] An operation method of an in-situ smoke sampling system for a biomass boiler is as follows: The vacuum pump 11 provides the power to extract the smoke, and the smoke enters the smoke sampling tube 2 through the constant speed sampling nozzle 1. The smoke temperature sensor 35 receives the smoke temperature signal and transmits it to the control processor 32. The control processor 32 adjusts the oil temperature and the oil temperature sensor 34 according to the oil temperature sensor 34, and controls the insulation oil in the insulation oil barrel 33 to enter the sampling insulation tube 31 to circulate and provide insulation effect, so as to ensure that the temperature of the high-temperature smoke in the smoke sampling tube 2 remains unchanged. The smoke passes through the smoke acceleration nozzle 7 arranged in the smoke sampling tube 2 to achieve the purpose of accelerating the smoke flow rate. In this process, due to inertia, the particles enter the fly ash collection device 6 through the fly ash sampling tube 5, and the smoke flows along the inner wall of the smoke sampling tube 2 and is discharged through the gas outlet 41; the connecting pipe 9 connects the fly ash collection device 6 and the smoke sampling tube 2 to balance the air pressure of the two, so as to achieve the purpose of smooth falling of the particles. Through the above process, in-situ smoke sampling of the biomass boiler is achieved, and it is ensured that no condensation of inorganic substances in the high-temperature flue gas occurs during this process, thereby achieving the purpose of separating the flue gas from the particles. Example

[0025] Based on the first embodiment, the similarities between this embodiment and the first embodiment are not repeated here. The differences are as follows: Since a flue gas acceleration nozzle 7 is provided above the fly ash sampling tube 5, the gas is accelerated at the flue gas acceleration nozzle 7, and the caliber of the fly ash sampling tube 5 is smaller than the flue gas acceleration nozzle 7, particulate matter may accumulate above the fly ash sampling tube 5 and cannot fall down the fly ash sampling tube 5 in time, which will cause the inlet of the fly ash sampling tube 5 to be blocked, affecting the sampling. In order to solve this problem, a sampling tube anti-blocking mechanism 8 is provided on the fly ash sampling tube 5. The specific structure of the sampling tube anti-blocking mechanism 8 is as follows: Figure 4 As shown, it includes an anti-blocking box 81, the upper end of the fly ash sampling tube 5 is movably penetrated and sleeved on the top of the anti-blocking box 81, and the lower end is fixedly penetrated and sleeved on the bottom of the anti-blocking box 81, and a piston block 811 is matched and sleeved in the anti-blocking box 81. The fly ash sampling tube 5 is fixedly penetrated and sleeved in the center of the piston block 811. The piston block 811 and the bottom wall of the anti-blocking box 81 form a negative pressure chamber 1, and the negative pressure chamber 1 is connected to the sampling main air pipe 10 through the air pipe 2 832. A compression spring 812 is sleeved on the fly ash sampling tube 5 located below the piston block 811 in the negative pressure chamber 1, and the piston block 811 is connected to the negative pressure chamber 1 through the compression spring 812. The pipe section of the fly ash sampling tube 5 located in the negative pressure chamber 1 is arranged as a telescopic pipeline structure. The upward or downward movement of the piston block 811 can drive the inlet of the fly ash sampling tube 5 to move toward or away from the flue gas acceleration nozzle 7.

[0026] The negative pressure chamber 1 of the anti-blocking box 81 is connected to the sampling main air pipe 10 through the auxiliary air pipe 83. When the system is in a normal pressure state, the piston block 811 does not move due to the elastic force of the compression spring 812. The vacuum pump 11 will first evacuate the smoke sampling tube 2 through the sampling main air pipe 10 to perform normal sampling. If the inlet of the fly ash sampling tube 5 is blocked and the top of the sampling main air pipe 10 is blocked, the vacuum pump 11 will continue to evacuate the gas in the negative pressure chamber 1, and the piston block 811 will overcome the elastic force of the compression spring 812 due to the pressure and move downward. Move, and at the same time drive the inlet of the fly ash sampling tube 5 to move downward and away from the flue gas acceleration nozzle 7. At this time, the gap between the fly ash sampling tube 5 and the flue gas acceleration nozzle 7 will become larger, and the particles accumulated and blocked above the fly ash sampling tube 5 will fall into the ventilation support 4. When the blockage above the fly ash sampling tube 5 disappears, the bottom of the smoke sampling tube 2 can continue to be ventilated, and the elastic force of the compression spring 812 pushes the piston block 811 back to its original position, driving the fly ash sampling tube 5 close to the outlet of the flue gas acceleration nozzle 7, and the system returns to normal pressure again to continue sampling.

[0027] Although the above-mentioned cooperation between the anti-blocking box 81 and the fly ash sampling tube 5 can avoid blockage, there is still a small problem: if there is a slight blockage above the fly ash sampling tube 5, these slight blockages can gradually pass through the fly ash sampling tube 5 smoothly through suction, but before being sucked away, the slight blockage will still cause a pressure difference in the anti-blocking box 81, and will still start the cooperation between the anti-blocking box 81 and the fly ash sampling tube 5 to drive the fly ash sampling tube 5 to move downward, which will cause the fly ash sampling tube 5 to be unable to continuously perform sampling. In order to solve this problem, a delayed start component 82 is set on the anti-blocking box 81.

[0028] The delayed start component 82 includes a sleeve 821, which is sealed and mounted on the outside of the anti-blocking box 81. A piston ring 822 is matched and mounted inside the sleeve 821. A negative pressure chamber 2 is formed between the piston ring 822 and the inner wall of the sleeve 821. The auxiliary air pipe 83 includes an air pipe 1 831 and an air pipe 2 832. The air pipe 1 831 is connected to the negative pressure chamber 2, and the air pipe 2 832 is connected to the negative pressure chamber 1. The air pipe 2 832 and the air pipe 1 831 are both connected to the sampling main air pipe 10. The negative pressure chamber 1 and the negative pressure chamber 2 can be connected to the sampling main air pipe 10 through the auxiliary air pipe 83, and a breathing hole 828 is opened on the top of the sleeve 821. A V-shaped rod 823 is arranged above the piston ring 822 in the sleeve 821. The outer end of the V-shaped rod 823 is hinged to the inner wall of the sleeve 821, and the inner end is hinged to a horizontally arranged clamping rod 824. The inner end of the clamping rod 824 is a downward inclined slope structure. The V-shaped rod 823 is connected to the sleeve 821 through a pull rope 826. The upper and lower ends of the pull rope 826 are respectively connected to the top wall of the sleeve 821 and the central hinge point of the V-shaped rod 823, and the piston ring 822 is connected to the central hinge position of the V-shaped rod 823 through a pull rope 827.

[0029] A guide sleeve 825 is fixed horizontally on the side wall of the anti-blocking box 81, and the clamping rod 824 is movably sleeved in the guide sleeve 825. Under the steady-pressure state, the position of the clamping rod 824 corresponds to the position of the piston block 811, and a positioning groove 813 is provided on the piston block 811. The clamping rod 824 can limit the position of the piston block 811 through the positioning groove 813 to prevent the piston block 811 from moving. When the fly ash sampling tube 5 is blocked and the anti-blocking box 81 is in a negative pressure state, since the position of the piston block 811 is limited, the gas in the negative pressure chamber 2 will be sucked away first, and the piston ring 822 will overcome the elastic force of the pull rope 826 and move downward. In the process of moving downward, the piston ring 822 will pull the V-shaped rod 823 through the pull rope 827 to move, thereby pulling the clamping rod 824 to gradually move outward. When the negative pressure reaches a certain state, that is, the blockage reaches a certain degree, the clamping rod 824 completely disengages from the positioning groove 813 to release the limiting fixation of the piston block 811, and then The piston block 811 is then sucked downward by the negative pressure, driving the fly ash sampling tube 5 to move downward away from the flue gas acceleration nozzle 7, so that the blocked particles can fall into the ventilation support 4. When the blockage is relieved, the system returns to normal pressure, and the piston block 811 and the piston ring 822 return to their original positions under the cooperation of the positioning groove 813 and the elastic force of the compression spring 812. Since the inner end of the clamping rod is a sloped structure, even if the return speed of the piston block is slower than that of the piston ring, the cooperation of the clamping rod and the clamping groove can make the piston block return to its original position and continue the sampling work in normal state. By cooperating with the delayed start component 82, a period of delay can be provided for the control between the anti-blocking box 81 and the fly ash sampling tube 5. If trace aggregated particles can gradually fall through the fly ash sampling tube 5, the negative pressure caused by the blockage of trace particles can be relieved by the operation of the delayed start component 82 alone. Then the piston block 811 will not drive the fly ash sampling tube 5 to move downward, so that the fly ash sampling tube 5 can maintain a normal sampling state; if there are many particles accumulated above the fly ash sampling tube 5, which cannot fall only by their own gravity and suction, the fly ash sampling tube 5 will be driven downward by the delayed start component 82 and the anti-blocking box 81 to remove the blockage. Through the above cooperation, the blockage phenomenon can be relieved without affecting the normal sampling of the fly ash sampling tube 5.

[0030] A limit assembly 84 for limiting the moving distance of the piston block 811 and the piston ring 822 is provided in the anti-blocking box 81 and the sleeve 821. The limit assembly 84 limits the moving distance and position of the piston block 811 and the piston ring 822, so that the piston block 811 and the piston ring 822 can stay at a limited position and cooperate with the sampling tube anti-blocking mechanism 8 to successfully complete the work.

[0031] When used specifically, during normal sampling, the position states of the fly ash sampling tube 5 and the sampling tube anti-blocking mechanism 8 are as follows: Figure 5As shown, the fly ash sampling tube 5 is close to the outlet of the flue gas acceleration nozzle 7. The smoke particles flowing in the smoke sampling tube 2 can be accelerated by the flue gas acceleration nozzle 7 and then introduced into the fly ash collection device 6 through the fly ash sampling tube 5 for collection. When the fly ash sampling tube 5 is blocked after sampling for a period of time, the vacuum pump 11 can first suck the air in the negative pressure chamber 2 through the air pipe 1 831, and the piston ring 822 overcomes the pulling force of the pull rope 826 and moves downward. During the downward movement of the piston ring 822, the V-shaped rod 823 is pulled around the central hinge point by the pull rope 827, and the clamping rod 824 is pulled outward synchronously. When the piston ring 822 moves down to a certain extent, the clamping rod 824 is completely disengaged from the positioning groove 813, and the restriction on the piston block 811 is released. Then the gas in the negative pressure chamber 1 will be sucked away through the air pipe 2 832, and the piston block 811 overcomes the elastic force of the compression spring 812 and moves downward, while driving the top of the fly ash sampling tube 5 to move downward, Figure 5 The status becomes Figure 6 The fly ash sampling tube 5 is away from the flue gas acceleration nozzle 7, and the particles blocked above fall into the ventilation support 4 through the enlarged gap. When the blockage disappears, the system returns to the stable pressure state, the piston block 811 and the piston ring 822 return to their original positions, and the fly ash sampling tube 5 is driven to become Figure 5 Normal sampling is performed in the state of Example

[0032] On the basis of the first embodiment, the connecting pipe 9 is connected between the fly ash collecting device 6 and the smoke sampling tube 2. During the sampling process, the smoke collected in the fly ash collecting device 6 may return to the smoke sampling tube 2 along the connecting pipe 9, or gather in the connecting pipe 9 to block the connecting pipe 9. In order to solve this problem, a filtering component is provided on the connecting pipe 9, such as Figure 7 As described, the connecting pipe 9 is disconnected at a position close to the fly ash collecting device 6, and filter boxes 15 that can be connected and spliced ​​together are installed at both ends of the disconnected position. A filter screen 16 is arranged in the filter box 15, and the filter screen 16 can prevent the smoke particles collected in the fly ash collecting device 6 from flowing back through the connecting pipe 9. Example

[0033] On the basis of the first embodiment, Figure 6 As shown, a filter screen 42 is provided in the gas outlet 41. When the fly ash sampling tube 5 is pulled downward by the sampling tube anti-blocking mechanism 8, the particles blocked above the fly ash sampling tube 5 will inevitably fall into the ventilation support 4. At this time, the filter screen 42 can intercept the particles and prevent them from flowing out along the gas outlet 41 and blocking the sampling main gas pipe 10 and the vacuum pump 11. The ventilation support 4 can be removed from the bottom of the smoke sampling tube 2. After the sampling is completed, the ventilation support 4 can be removed to clean the particles left inside.

[0034] The above description is only a preferred embodiment of the present invention and does not limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An in-situ flue gas sampling system for a biomass boiler, comprising an isokinetic sampling nozzle (1) and a smoke sampling tube (2), wherein the isokinetic sampling nozzle (1) is connected to the smoke sampling tube (2), and is characterized in that: It also comprises a flue gas heat preservation unit (3) and a fly ash collection device (6); a ventilation support (4) is installed at the bottom of the smoke sampling tube (2); a gas pipe joint (43) is arranged at the bottom of the ventilation support (4); a gas outlet (41) is provided on the ventilation support (4) and located inside the gas pipe joint (43); the gas pipe joint (43) is connected to an external vacuum pump (11) through a sampling main gas pipe (10); a gas flow control valve (12) is installed on the sampling main gas pipe (10); a fly ash sampling tube (5) is installed on the bottom end of the smoke sampling tube (2) through the ventilation support (4); The lower part of the fly ash sampling tube (5) is inserted into the fly ash collecting device (6); a flue gas acceleration nozzle (7) is arranged inside the lower end of the smoke sampling tube (2); the upper end of the fly ash sampling tube (5) is located at the lower air outlet of the flue gas acceleration nozzle (7); the flue gas acceleration nozzle (7) is used to accelerate the flow velocity of the sampled flue gas; the flue gas insulation unit (3) comprises a sampling insulation tube (31) and an insulation oil barrel (33); the sampling insulation tube (31) is sleeved on the outer side of the smoke sampling tube (2); the insulation oil in the insulation oil barrel (33) can enter the sampling insulation tube (31) to provide insulation for the smoke sampling tube (2); The fly ash sampling tube (5) is provided with a sampling tube anti-blocking mechanism (8), comprising an anti-blocking box (81) and a delayed start component (821) which are mutually sleeved. The upper end of the fly ash sampling tube (5) movably penetrates the top of the anti-blocking box (81), and the lower end is fixedly penetrated through the bottom of the anti-blocking box (81). A piston block (811) is matched and sleeved in the anti-blocking box (81). The fly ash sampling tube (5) is fixedly penetrated and sleeved in the center of the piston block (811). The piston block (811) and the anti-blocking box (821) are connected to each other. 1), and the negative pressure chamber 1 is connected to the sampling main air pipe (10) through the air pipe 2 (832); a compression spring (812) is mounted on the fly ash sampling tube (5) below the piston block (811) in the negative pressure chamber 1; the piston block (811) is connected to the negative pressure chamber 1 through the compression spring (812); when the upper part of the fly ash sampling tube (5) is blocked by particulate matter, the piston block (811) moves downward due to the negative pressure, which can drive the top end of the fly ash sampling tube (5) to move downward, causing the blockage to fall; A piston ring (822) is matched and mounted inside the delayed start component (821), and a second negative pressure chamber is formed between the piston ring (822) and the delayed start component (821). The second negative pressure chamber is connected to the sampling main air pipe (10) through the air pipe (831). A limiter component for positioning the piston block (811) is arranged above the piston ring (822). The piston ring (822) moves up and down to enable the limiter component to limit or release the limit on the piston block (811). When negative pressure occurs in the system due to blockage, the delayed start component (821) is first started by the negative pressure, and the limiter component first releases the limit on the piston block (811). Then, the piston block (811) is started again to drive the fly ash sampling tube (5) to move downward. The delayed start component (821) can provide an extended time for the cooperation between the anti-blocking box (81) and the fly ash sampling tube (5).

2. The biomass boiler in-situ flue gas sampling system according to claim 1 is characterized in that: A V-shaped rod (823) is arranged above the piston ring (822) in the delayed start assembly (82). The outer end of the V-shaped rod (823) is hinged to the inner wall of the sleeve (821), and the inner end is hinged to a horizontally arranged clamping rod (824). The inner end of the clamping rod (824) is a downwardly inclined inclined surface structure. The V-shaped rod (823) is connected to the sleeve (821) through a pull rope (826), and the piston ring (822) is connected to the sleeve (821) through a pull rope (826). The rope (827) is connected to the V-shaped rod (823); a guide sleeve (825) is fixed to the side wall of the anti-blocking box (81); a clamping rod (824) is movably sleeved in the guide sleeve (825); in a stable pressure state, the position of the clamping rod (824) corresponds to the position of the piston block (811); and a positioning groove (813) is provided on the piston block (811); the clamping rod (824) can limit the piston block (811) through the positioning groove (813).

3. The biomass boiler in-situ flue gas sampling system according to claim 1 is characterized in that: The sampling insulation tube (31) is composed of an outer tube (311) and a middle tube (312) which are sleeved together, and an insulation oil passage (313) is retained between the outer tube (311) and the middle tube (312). An insulation oil inlet (314) is welded to the side of the outer tube (311), and an insulation oil outlet (315) is welded to the side of the middle tube (312). The insulation oil barrel (33) is connected to the insulation oil inlet (314) and the insulation oil outlet (315) through oil pipes, respectively. The insulation oil in the insulation oil barrel (33) enters the insulation oil passage (313) through the insulation oil inlet (314), and then flows out through the insulation oil outlet (315), thereby forming an insulation oil circulation.

4. The biomass boiler in-situ flue gas sampling system according to claim 3 is characterized in that: A smoke temperature sensor (35) is installed on the top of the smoke insulation unit (3), and an oil temperature sensor (34) is installed on the insulation oil barrel (33). The smoke temperature sensor (35) and the oil temperature sensor (34) are used to measure the temperatures of the smoke and insulation oil, thereby ensuring that the insulation temperature of the smoke insulation unit (3) is the same as the smoke temperature.

5. The biomass boiler in-situ flue gas sampling system according to claim 1 is characterized in that: A connecting pipe (9) is connected between the fly ash collection device (6) and the smoke sampling tube (2), and the connecting pipe (9) connects the upper part of the smoke acceleration nozzle (7) in the smoke sampling tube (2) with the fly ash collection device (6) from the side, forming a loop for balancing the pressure of the smoke sampling tube (2) and the fly ash sampling tube (5).

6. The biomass boiler in-situ flue gas sampling system according to claim 2 is characterized in that: The anti-blocking box (81) and the delayed start assembly (82) are provided with a limit assembly (84) for limiting the movement range of the piston block (811) and the piston ring (822); the limit assembly (84) can limit the movement distance and position of the piston block (811) and the piston ring (822).

7. The biomass boiler in-situ flue gas sampling system according to claim 1 is characterized in that: The connecting pipe (9) is disconnected at a position close to the fly ash collecting device (6), and a filter box (15) is installed at the disconnected position. A second filter screen (16) is arranged in the filter box (15), and the second filter screen (16) can prevent smoke particles from flowing back through the connecting pipe (9).

8. The biomass boiler in-situ flue gas sampling system according to claim 1 is characterized in that: A filter screen 1 (42) is provided in the gas outlet (41), and the ventilation support (4) can be removed from the bottom of the smoke sampling tube (2).

9. The method for operating the biomass boiler in-situ flue gas sampling system according to claim 1, characterized in that: The following operations are performed: the vacuum pump (11) provides power for extracting smoke, and the smoke enters the smoke sampling tube (2) through the isokinetic sampling nozzle (1). The smoke temperature sensor (35) receives the smoke temperature signal and transmits it to the control processor (32). The control processor (32) adjusts the oil temperature and the oil temperature sensor (34) according to the oil temperature sensor (34), and controls the insulation oil in the insulation oil barrel (33) to enter the sampling insulation tube (31) for circulation to provide insulation effect, thereby ensuring that the temperature of the high-temperature smoke in the smoke sampling tube (2) remains unchanged; the smoke passes through the smoke acceleration nozzle (7) arranged in the smoke sampling tube (2), thereby achieving the purpose of accelerating the smoke flow rate. In this process, due to inertia, particulate matter enters the fly ash collection device (6) through the fly ash sampling tube (5), and the smoke flows along the inner wall of the smoke sampling tube (2) and is discharged through the gas outlet (41); The connecting pipe (9) connects the fly ash collection device (6) and the smoke sampling pipe (2) to balance the air pressure of the two, so as to achieve the purpose of smooth falling of particles. Through the above process, the in-situ smoke sampling of the biomass boiler is achieved.

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